Apparatus for rectifying alternating electric currents



| H. PETER March 10, 1931.

APPARATUSFOR RECTIFYING ALTERNATING ELECTRIC CURRENTS Filed Nov. 15 1928 I5 15 I5 Z5 Z3 Z5 15 15' I522 My}; ATTORNEY Patented Man 1Q, 1931 UNITED STATES PATENT OFFICE LESLIE HUBST PETER, OF-LONDON, ENGLAND; ASSIGNOR, BY MESNE ASSIGNMENTS,

TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE,

CORPORATION OF PENNSYLVANIA PENNSYLVANIA, A

APPARATUS ZEOIR. RECTIFYIN G ALTERNATING ELECTRIC CURRENTS Application filed November 15, 1928, Serial No. 319,524, and in Great Britain December 19, 1927.

My invention relates to apparatus for rectifying alternating electric currents of the kind comprising rectifying elements each consisting of a metal member having a layer tive to the central disc'orplate as to constltute radiating fins or heat conducting ele-' ments whereby the heat generated by the passage of current through the rectifying 1 element can be dissipated and the apparatus of a compound of the metal formed thereon, the invention having for its object to thus maintained at the desired operating provide certain improvements in rectifying temperature.

apparatus of this character. The invention is illustrated by way of ex- The rectifying elements preferably con- 0 sist of metal discs or plates and as hitherto constructed one face or side only of each disc or plate is covered with a layer or coating of the compound, the other uncovered face or side being utilized to effect the electrical connection of the element with the next adjacent element of a series, the rectifying apparatus thus comprising a column of rectifying elements superposed upon one another in the well known manner.

\According to the principal'feature of the present invention, however, both sides of each member are provided witha layer or coating of compound, a conducting member composed of metal or other suitable material being placed on each side of the coated member, the two conducting members being electrically connected with one another. The improved rectifying element thus formed consists of a central coated member preferably in the forin ofa plate or disc forming one terminal of the element and a pair of electrically connected conducting members also in the form of discs or latesengaging with the opposite coated surfaces of the central member and constituting the other terminal of the element. It will be evident that with-this arrangement the coating of both sides of the central member'is available as a rectifying surfacev and the contact area for rectification is thus doubled for a given size of disc or plate.

According to a further feature of the invention the conducting discs or plates in engagement with the coated discs or plates or each side thereof are utilized not only electrically asabove described but also thermally for the purpose of enabling the heatgenerated in the element during operation to be dissipated, the conducting discs or plates being preferably of such extended form relaapplied to the rectification ample in the accom anying drawm s of which Fig. 1 is a vie v in side elevati dn of one form of rectifying apparatus embody ing the invention, Fig. 2 being a view thereof in end elevation.

Fig. 3 is a sectional view on the line elements constituted by circular copper washers 1, both faces ofwhich are covered with a layer of cuprous oxide formed directlythereon. These washers the number of which corresponds to the voltage of the curof three-phase rent to be rectified; are arranged adjacent and parallel to one another upon a central spindle or bolt 2 covered with an insulating sleeve or tube" 3. On each side of each washer 1 is arranged a disc of brass or other conducting material of considerably greater diameter than the'washer 1 a relatively thin washer 4'of lead or other suitable material being interposed between the oxidized face' of the Washer 1 and the conducting disc. Between each of the composite rectifying elements thus formed and the next adjacent element a washer'5 of any suitable electrically insulating material is interposed and the series of elements thusformed are held in intimate engagementwith one another by suitable en plates 6, 7 spring washers 8, and .nuts 9 at each end of the supporting spindleor bolt 2.

The conducting "discs above referred to as' provided on each side. of each of the copper washers 1 areof the forms shown in Figs. 2 and 3, certain of these discs 10 having slots or recesses 11, 12 at two portions of their periphery as shown in Fig. 2. Certain other discs 13 have only a single slot or recess 14 as indicated in Fig. 3 while other discs 15 have a single slot in the relative position indicated in dotted lines at. 16 in Fig. 3.

-The manner in which the several forms of discs above referred to are arranged is indicated in Fig. 4 from which it will be seen that the end discs of the row or column, the four discs at the center thereof and each alternate disc of the remainder are of the form indicated at 10 in Fig. 2 while the other discs are of the forms indicated by the reference numerals 13 and 15 above referred to.

Each of the co per washers 1 is provided with a lug 16 rom both sides of which the oxide coating has been removed, this lug serving for effecting the electrical connection of the washers 1 together as shown in the diagram of Fig. 4. This connection is effected by means of wires 17 and the slots or recesses 11, 12, 14, 16 are provided in the conducting discs 10, 13, 15 for facilitating the arrangement of these conducting wires 17 so as to economize space and to prevent any possibility of a short-circuit.

The conducting discs 10,13 or 10, 15 of each rectifying element on opposite sides of each of the copper washers 1 are arranged to be electrically connected together by means of relatively small metal washers 18 interposed between each pair of discs and mounted upon a second spindle 19 provided with an insulating sleeve 20 and traversing the whole series of rectifying elements, suitable spacing washers 21 of insulating material being interposed between the conducting disc of one rectifying element and that of the next adjacent element.

Referring again to Fig. 4 it will be seen that in order to obtain full-wave rectification the electrical connections of the several rectifying elements in one half of the row or column of elements is the reverse of that in the other half, the four central conducting discs 10 being electrically connected together by the'washers '18 (Fig. 1) to constitute the negative terminal 22 of the rectifier while the end washers are connected to conductors 23 constituting the positive terminal.

The conducting discs 13, 15 at the electrical centers of the two halves of the rectifier are provided with conductors 24, 25 constituting the alternating current terminals of the apparatus.

In cases in which the several rectifying eleinents are to be connected in parallel instead of in series with one another as above described the several conducting discs may be arranged to be all electrically connected for instance by conducting washers mounted upon a spindle traversing the whole series of discs, the central copper washer of the elements being electrically connected together in any suitable manner.

A similar arrangement to that described above may evidently also be adopted for rectifying poly-phase currents, the rectifying elements being divided into groups corresponding to each phase, the terminals of these groups being suitably connected.

In the case of a three-phase alternating current for instance the arrangement of connections shown in Fig. 5 may be adopted. The current to be rectified is supplied to the primary winding of a three-phase transformer or group of transformers, the secondary winding 26, 27, 28 of which are starconnected as shown. Each of the windings 26, 27, 28 is-connected to a suitably star-connected group of rectifiers 29, 30, 31 by conductors 32, 33, 34, respectively, the load circuit 35 being connected across the neutral points 36, 37 of the transformer secondary windings and of the rectifier.

The rectifying ap aratus constructed as above described may arranged to operate either in air or may be immersed in. oil contained in a suitable tank or other receptacle, the conductingdiscs in either case serving as fins to dissipate the heat generated in the rectifying elements during operation.

The invention is evidently not limited to the particular constructional arrangements above described and illustrated which may be varied in many respects without exceeding the scope of the invention.

Having now particularly described and ascertained the nature of my said invention and in what manner the'same is to be performed, I declare that what I claim is:

An electrical rectifier comprising an insulated rod, a plurality of rectifying elements mounted on said rod and each consisting of a metal member having a layer of a compound of the metal forme on each surface thereof, each member beings rovided with a peripheral lug, metallic dis farger in diameter than said rectifying elements and one being located on each sideof each element, each disk having a peripheral recess to facilitate the electrical connectionof the lug 1 15 1 

